The present invention relates to a rotating electric machine configured to include a stator and a rotor, and relates more specifically to a multi-coolant type rotating electric machine having a structure of cooling the rotating electric machine using plural kinds of coolant.
In the past, as a rotating electric machine having a structure of cooling the rotating electric machine using two kinds of liquid coolant A and B and employing a cooling method of reserving the liquid coolant B inside the rotating electric machine and cooling the inside of the rotating electric machine, there was one strengthening the cooling capacity by arranging a flow passage for circulating the liquid coolant A through a bracket that was a frame of the end section of the rotating electric machine (refer to JP-A-2012-191718 for example).
Also, in the past, as a rotating electric machine employing a cooling method of reserving the liquid coolant B in the inside of the rotating electric machine and cooling the inside of the rotating electric machine in a similar manner, there was one strengthening the cooling capacity by lifting the liquid coolant B inside the rotating electric machine by pumps arranged on a shall disposed on the inner circumference side of the rotor to the upper part inside the rotating electric machine for cooling (refer to JP-A-2012-191719 for example).
Also, in the past, as a rotating electric machine employing a cooling method of reserving the liquid coolant B in the inside of the rotating electric machine and cooling the inside of the rotating electric machine in a similar manner, there was one strengthening the cooling capacity by disposing a pump formed of a vane member in a bracket that was a frame in the end section of the rotating electric machine, rotating the pump by the flow of the cooling water of the liquid coolant A, and lifting the liquid coolant B inside the rotating electric machine to the upper part inside the rotating electric machine for cooling (refer to JP-A-2013-162674 for example).
In general, as a method for introducing a liquid coolant into a machine for cooling in a rotating electric machine, there are three methods as described below.
(1) A method for cooling the surface outside the rotating electric machine by arranging a pump A arranged outside the rotating electric machine and a cooler A cooling the liquid coolant A circulated through a cooling frame formed on the surface outside the rotating electric machine, and circulating the liquid coolant A cooled by the cooler A through the cooling frame by the pump A.(2) A method for cooling the inside of the rotating electric machine by arranging a pump B arranged outside the rotating electric machine and a cooler B cooling the liquid coolant B circulated through the inside of the rotating electric machine, and circulating the liquid coolant B cooled by the cooler B through the inside of the rotating electric machine by the pump B.(3) A method for cooling the surface outside the rotating electric machine and the inside of the rotating electric machine by using both methods of (1) and (2) simultaneously.
When the cooling method of (1) is called “oil cooling”, the cooling method of (2) is called “water cooling”, and the cooling method of (3) is called “cooling by both oil cooling and water cooling”, each of them has the features as described below in general.
Water cooling is a cooling method for cooling a heat generation source such as a conduction loss generated when electric current is made to pass through a stator coil inside a rotating electric machine, an iron loss generated by that the magnetic flux passes through a stator core, and so on through the stator core, and cooling can be strengthened more compared to air cooling in which cooling is performed by a gas coolant inside the rotating electric machine.
With respect to oil cooling, because a heat generation source such as a conduction loss generated when electric current is made to pass through a stator coil inside the rotating electric machine, an iron loss generated by that the magnetic flux passes through the stator core, and so on is directly cooled, cooling can be strengthened compared to water cooling.
Because cooling by both oil cooling and water cooling uses both of oil cooling and water cooling simultaneously, cooling of the inside of the rotating electric machine by oil cooling and cooling of the surface outside the rotating electric machine by water cooling can be performed, and therefore cooling can be strengthened compared to water cooling and oil cooling. On the other hand, in codling by both oil cooling and water cooling, there is a problem that the system becomes large because the pump A and the pump B are required.
In order to solve the problem, cooling methods of reserving the liquid coolant B in the inside of the rotating electric machine and cooling the inside of the rotating electric machine have been disclosed in JP-A-2012-191718, JP-A-2012-491719, and JP-A-2013-162674. According to the cooling method disclosed in JP-A-2012-191718, it is characterized that a flow passage for circulating the liquid coolant A through a bracket that is a frame in the end section of the rotating electric machine is arranged, and cooling is strengthened. According to the cooling method disclosed in JP-A-2012-191719, it is characterized that the liquid coolant B inside the rotating electric machine is lifted by pumps arranged on a shaft disposed on the inner circumference side of the rotor to the upper part in the inside of the rotating electric machine for cooling, and cooling is strengthened. According to the cooling method disclosed in JP-A-2013-162674, it is characterized that a pump formed of a vane member is disposed in a bracket that is a frame in the end section of the rotating electric machine, the pump is rotated by the flow of the cooling water of the liquid coolant A, and the liquid coolant B inside the rotating electric machine is lifted to the upper part of the inside of the rotating electric machine for cooling, and cooling is strengthened.
However, according to the configuration described in JP-A-2012-191718, because it is configured that the liquid coolant is circulated through the bracket also, there is a problem that the structure of the bracket becomes complicated and the cost increases. Also, according to the configuration described in JP-A-2012-191719, there is a problem that the rotating electric machine becomes large by the pumps arranged on the shaft. Further, according to the configuration described in JP-A-2013-162674, although it is configured that the liquid coolant B inside the rotating electric machine is lifted to the upper part in the inside of the rotating electric machine by the pump formed in the bracket, because the flow passage of the liquid coolant B is the bracket, there is a problem that the bracket becomes complicated and the cost increases.